open-nomad/command/data_format.go

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package command
import (
"bytes"
"encoding/json"
"fmt"
"io"
"text/template"
)
//DataFormatter is a transformer of the data.
type DataFormatter interface {
// TransformData should return transformed string data.
TransformData(interface{}) (string, error)
}
// DataFormat returns the data formatter specified format.
func DataFormat(format, tmpl string) (DataFormatter, error) {
switch format {
case "json":
return &JSONFormat{}, nil
case "template":
return &TemplateFormat{tmpl}, nil
}
return nil, fmt.Errorf("Unsupported format is specified.")
}
type JSONFormat struct {
}
// TransformData returns JSON format string data.
func (p *JSONFormat) TransformData(data interface{}) (string, error) {
out, err := json.MarshalIndent(&data, "", " ")
if err != nil {
return "", err
}
return string(out), nil
}
type TemplateFormat struct {
tmpl string
}
// TransformData returns template format string data.
func (p *TemplateFormat) TransformData(data interface{}) (string, error) {
var out io.Writer = new(bytes.Buffer)
if len(p.tmpl) == 0 {
return "", fmt.Errorf("template needs to be specified the golang templates.")
}
t := template.Must(template.New("format").Parse(p.tmpl))
err := t.Execute(out, data)
if err != nil {
return "", err
}
return fmt.Sprint(out), nil
}